TW411329B - Process for the production of vinyl acetate - Google Patents

Abstract

A process for the production of vinyl acetate which comprises contacting ethylene, acetic acid and an oxygen-containing gas with a supported palladium catalyst prepared by a process comprising the steps of (a) impregnating a catalyst support with a palladium compound (b) converting the palladium compound to substantially metallic palladium, and (c) sintering the supported palladium at a temperature of greater than 500 DEG C.

Description

41132S at ___B7_ Printed by the Central Consumers Bureau, Ministry of Economic Affairs, Consumer Cooperatives V. Description of the Invention (1) The present invention relates to a method for producing vinyl acetate by contacting ethylene, acetic acid, and an oxygen-containing gas with a supported palladium catalyst. The manufacture of a supported palladium catalyst for the preparation of vinyl acetate usually involves impregnating a suitable support with a palladium compound, and then converting the palladium compound into palladium which is substantially metal. Methods for manufacturing shell-impregnated catalysts are described in, for example, US3822308, US4048096, US5185308, US5332710, CA2128162, US4087622, CA2128154, CA2128161, and US5422329. Methods for manufacturing non-shell catalysts are described in, for example, US3743607, GBI333449, US3939199, US4668819, EP330853, EP403950, EP431478, and CA2071698. US5336802 describes a method for pretreating a palladium-gold catalyst, wherein the catalyst is in the presence of an oxidant such as air and is heated at a temperature at least sufficient to partially oxidize the palladium; the oxidant is recovered and an inert gas such as nitrogen is introduced The catalyst is heated again at a temperature of up to 500 ° C and in the presence of a reducing agent such as hydrogen or ethylene. The method is exemplified by "a conventional catalyst containing generally 1% of palladium and 0.5% of gold". The activity of the production of vinyl acetate of a known supported palladium catalyst is reduced due to use. If the catalyst activity and process productivity are reduced to a commercially unacceptable level, it must regenerate and / or replace the catalyst. The purification of ethyl acetate is described in Chem. Eng. Technol. 17 (1994) 112-118 by Abel et al. This paper size applies to the ten countries' national standard (CNS) A4 specification (210X297 mm) -------------- IT ------ c-(Please read the note on the back first Please fill out this page again) Printed by the Central Standards Bureau of the Ministry of Economic Affairs, Shellfish Consumer Cooperative 411329 Α7 ___ B7 V. Description of the Invention (2) There is a problem in increasing the life of the catalyst only by increasing the palladium content in the catalyst. In the meantime, for example, The factory's limited heat removal capability, the initial activity of the catalyst is too high for safe and / or industrially controlled operations. There is a palladium for the production of vinyl acetate that overcomes this problem Demand for a catalyst manufacturing method "Therefore, according to the present invention, there is provided a method for manufacturing vinyl acetate, the method comprising contacting ethylene, acetic acid, and an oxygen-containing gas with a supported palladium catalyst, the catalyst being prepared by : (A) impregnating the catalyst body with a boat compound, (b) converting the palladium compound into substantially metallic palladium, and (C) sintering the supported palladium at a temperature greater than 500 ° C. The present invention is 500 ° C temperature will Sintered on this support to solve the technical problem defined above. Without intending to be limited by any theory, it is believed that this sintering step causes the growth of palladium metal particles, which reduces the initial activity of the catalyst. Therefore, it has a high palladium concentration but is commercially acceptable The starting active catalyst can be prepared by the method according to the present invention, and the catalyst has a longer commercially usable life than traditional catalysts. The sintering step also increases the average pore size of the silica support. The present invention The catalyst has also been found to be less susceptible to the adverse effects of excessive concentrations of promoters such as potassium acetate. The sintering step (C) is preferably carried out using a reducing gas, but can also be carried out in the presence of an oxidizing gas or in an inert gas. 。The appropriate reducing gas is hydrogen and carbon monoxide. The suitable oxidizing gas is oxygen》 These can be inert on this paper scale. Applicable to China National Standard (CNS) M specifications (210 × 297 mm) --------_ % 11 * 1 (Please read the notes on the back before filling this page) Order

41132S ~ A7 D ^ ------- B7 V. Description of the invention (3)-It is diluted by gas. Suitable inert gases which can be used alone or in combination with an oxidizing or reducing gas are nitrogen, carbon dioxide and hydrogen. A suitable temperature for the sintering step is greater than 500 ° C to 10,000. (^ The preferred temperature range is 65010000C. The preferred time for the sintering step is between 24 hours and 24 hours. If an oxidant is used, the catalyst needs to be substantially reduced. Before sintering and Heating (for safety) and cooling (less than i 00. [, more preferably less than 6 < rc) can be purged with inert gas to avoid redispersion of palladium. Any suitable or feasible heating or cooling rate can be used The commercial sintering step (c) can be implemented in a tower or container that can meet the above-mentioned processing conditions. The catalyst can be stirred by air flow during the processing. The rotary spiral furnace can be used. In the laboratory specifications, if gas_solid When the contact is valid (length / diameter needs to be considered), the tube placed horizontally or vertically in the electric furnace can be used. Preheating gas flow may be required. The time of the sintering step is related to the temperature; higher temperatures are required Shorter time. Those skilled in the art can use these parameters to meet operating specifications. Typically, the sintering step (c) causes the diameter of the palladium metal particles to grow from 3-4 nm to 8-15 nm. Step (b) t of Palladium The conversion of metal to palladium, which is essentially a metal, can be achieved by a reduction step, which can be immediately followed by the sintering step (c) and the two methods can be performed by the same device. The method for producing the catalyst of the present invention can be used to produce a uniform impregnation Or shell-impregnated catalyst, which is used for the fluidized bed or fixed bed method of manufacturing vinyl acetate Specifications {2 丨 〇 > < 297 mm)-< " (Please read the notes on the back before filling this page) Printed by the Office of the Consumer Cooperative, 411329 at B7 V. Description of the invention (4) The catalyst, for example, based on the total weight of the catalyst, is more than 0.5% by weight, preferably more than 1% by weight. The palladium concentration can be as high as 5% by weight for fluidized beds and as high as 10% by weight for fixed bed operations. If manufactured by conventional methods, the starting activity of a supported palladium catalyst with a high palladium concentration is expected to be very high, even as high as unsafe and / or uncontrollable for high industry specifications. However, when manufactured by the method of the present invention, the initial activity of the catalyst is reduced compared to conventionally manufactured catalysts. For the desired life of the catalyst, a high palladium concentration results in a highly acceptable activity. In order to make a shell-impregnated and uniformly impregnated catalyst, suitable catalyst supports include pore-like stone siesta, oxidized charm, dream stone / sand oxide, oxidized oxide, oxidized oxide, or carbon, preferably silica. Where applicable, the pore size of the support may be 0.2 to 3,5 ml per gram of support, the surface area is 5 to 800 square meters per gram of support, and the apparent bulk density is 0.3 to 1.5 g / ml. For catalysts used in fixed bed processes, the support typically has a size of 3 to 9 mm. For catalysts used in fixed bed processes, the support can typically be spherical, bond, extrudate, pellet-shaped, or any suitable shape. For catalysts used in fluidized bed processes, the support may typically have at least 60% of the catalyst particles having a particle diameter of less than 200 microns, preferably at least 50% less than 105 microns and not more than 40 microns. % Of catalyst particles have a particle size distribution of less than 40 microns. In step (a), the support is preferably in a suitable solvent to impregnate the compound. Suitable solvents may be water, carboxylic acids (such as acetic acid), benzene, toluene, alcohols (such as acetic acid or ethanol), nitriles (such as' acetonitrile or 3M CNS for this paper), A4 (21GX297) p (Please read the notes on the back before filling in this page) ---- Order 411329

5. Description of the invention (5 y benzonitrile), tetrahydrofuran or chlorinated solvents (such as digas methylbenzene). Preferably, the solvent is water and / or acetic acid β, and the acetate, sulfate, nitrate, vapor, or argon-containing palladium salt (such as H2pdC14, Na2PdC14, or K2PdC14) is suitable. The soluble compound is Na2PdC14. The preferred acetic acid-soluble palladium compound is palladium acetate. The impregnation of the support can be carried out by immersion, immersion, or contact with the support in contact with the compound solution. The impregnation can be one or several The steps can be implemented in a continuous method. The building can be contacted with the impregnated solution by rolling, rotating, vortexing or similar methods to produce a uniform impregnation. The impregnation is typically performed at ambient temperature. Raising The temperature can be the same as, for example, the use of acetic acid in acetic acid, up to 120 ° C, preferably up to 100 ° C, more preferably up to 60 ° C. Impregnation needs to be performed carefully, so 'avoid supporting Rupture or abrasion of the body. The support can be filled to 5-100% of the pore volume by the impregnation solution. »In addition to the palladium compound, the support can also be prepared in step (a) with gold, copper and / or nickel compounds ( Preferred is gold) impregnation, which is converted into palladium with step (b) Metal and exists as a mixture and / or alloy with the metal palladium particles. Suitable gold compounds include vaporized gold, tetragas metal (HauC14 'NaAuC14' KAuC14), gold dimethyl acetate, barium acetamate or Gold acetate 'is preferably HAuC14. These promoters can be used in an amount of 0.1-10% by weight of each metal present in the final catalyst. Except for palladium and selective gold, copper and / or nickel, during the manufacturing process At any appropriate stage, it can be impregnated with one or more salts of Group I and II 'lanthanides or transition metals, preferably cadmium, barium' potassium, sodium, iron, -8. Standard (CNS) A4 specification (210X 297 public holidays) ---------- (please read the notice on the back of the t before filling out this page) Order the Central Standards Bureau of the Ministry of Economic Affairs and the Ministry of Economic Affairs Printed by the Central Bureau of Standards Shellfish Consumer Cooperative 411329 Α7 B7 V. Description of the Invention (6) Manganese, nickel, antimony and / or lanthanum are present as salts (typically acetic acid) in the final catalyst. Generally potassium will be present << Suitable salts of these compounds are acetate or gasification However, any suitable salt may be used. These promoters may be present in the final catalyst in an amount of 0.5% by weight (preferably 3-9% by weight) per promoter salt. If Requires a higher solubility of palladium or accelerator than the salt in the solvent. The impregnated support can be selectively dried and the impregnation step can be repeated two or more times. The drying step can be up to 120 ° C (Preferably up to C100 C 'best is 60 C). Drying step is performed at ambient temperature and reduced pressure. Air, nitrogen, helium, carbon dioxide or any suitable inert gas can be used in the drying step. . The catalyst can be tumbled, spun, or agitated to assist drying. In order to make a shell impregnation catalyst, a wet or dry impregnation support system is contacted with an alkaline solution by swirling, rolling, rotating, mixing, etc. The alkaline solution can also be sprayed on the impregnated support during rolling, rotating, mixing, etc. The test may be a hydroxide, carbonate or dream salt of group I or II. Typical examples are carbon hydroxide and sodium silicate. Potassium hydroxide, potassium silicate, and barium hydroxide can be applied in one or more steps with an appropriate delay between applications. The temperature of the precipitation step is usually the ambient temperature, but it can be raised up to the maximum: Any solvent can be used in which the analytical material is soluble, preferably water. The alkaline material needs to be in contact with the impregnated support body for a proper time. In this way, the metal salt can be precipitated in the shell β, which usually takes more than 1 hour, preferably between 8 and 24 hours. For precipitation, the best amount of alkaline material is required. 9- This paper size is in accordance with the Chinese National Standard (CNS) Α4 specification (2ι〇χ297 public epidemic) ---------- (Please read the note on the back first Please fill in this page again) Order 1 Printed by the Central Standards Bureau of the Ministry of Economic Affairs, Shellfish Consumer Cooperative Co., Ltd. 411328 a7 —__ B7_ V. Description of the Invention T ^ ~) —— The amount of material is usually too much, and it is generally used to produce metal salt gas oxidation 1.8 times the amount required for the substance "The impregnated support can be washed to remove anionic contaminants, such as nitrates, sulfates and general autogenous compounds. For chloride removal, rinse with deionized water until the silver nitrate test shows no chloride is present. The amount of anionic contaminants should be minimized. Cationic contaminants need to be minimized, for example, to less than 0.5% by weight, preferably less than 0,2% by weight of sodium in the dry catalyst. Low levels of these pollutants may be maintained, and their content is absolutely zero. "In commercial specifications, batch cleaning can be used β to speed up the process, warm water β can be used, and ion exchange Solutions such as 'potassium acetate' can be used instead of chloride and sodium. Furthermore, the reagents used in the preparation can be selected to avoid the use of vapors and sodium, for example, replacing potassium salts with potassium silicate. At step (b) t, the palladium compound can be converted to a metal before or after the above selective washing step (depending on the reagent used). A liquid reducing agent which can be used, such as, water-soluble hydrazine, T-aldehyde, sodium formate, methanol or alcohol, is preferably water-soluble hydrazine. The reduction reaction can also be performed using a gas such as carbon monoxide, argon, and ethylene. These can be diluted with an inert gas such as nitrogen, dioxide or helium. Typically, the gas reduction reaction is performed at an elevated temperature of 100-500 ° C until the substance is reduced. Typically, the reduction reaction in the liquid reducing agent occurs at ambient temperature, but temperatures up to 100 ° C can be used. After Yu Ji is converted to metal, it is sintered as described herein. -10- This paper size applies Chinese National Standard (CNS) A4 scale (2 丨 0.〆297mm) ------------ OI-I (Please read the precautions on the back before (Fill in this page) Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 1ί11329 at f Β7 V. Description of the invention (8) The sintering step (C) can be performed after step (b) by further heating the catalyst in the reducing gas to Above 500 ° C. The material can be impregnated with an accelerator as described above. Ethylene, acetic acid, and an oxygen-containing gas may be contacted with a palladium catalyst supported by a catalyst produced in accordance with the catalyst manufacturing method of the present invention in a manner known in the art. Therefore, the reactant can be brought into contact with the catalyst in a fixed or fluidized bed at a temperature of 145 to 195 ° C and a pressure of 1 atm to 20 atm. Ethyl acetate products can be recovered by conventional methods known to those skilled in the art. The invention will be illustrated with reference to Figures 1 to 3 and the following examples and experiments. Figure 1 illustrates some possible catalyst manufacturing methods according to the present invention. Figure 2 illustrates a comparison of the productivity of a catalyst manufactured according to the present invention with time as a function of a catalyst manufactured according to the present invention. Figure 3 is a graphical illustration of the comparison of the effect of the promoter potassium acetate on the activity of a catalyst made according to the present invention compared to the activity of a catalyst not made according to the present invention. Referring to Figure 1, a homogeneous (non-shell) type catalyst can be manufactured by impregnating the support with a palladium salt and a selective promoter, and then drying and reducing the metals. This material can then be optionally washed and dried before sintering according to the invention, and finally impregnated with a selective accelerator such as an acetate of potassium, sodium, cadmium or barium. To make a shell catalyst, the support impregnated with palladium and optionally a promoter such as gold can be selectively dried. The metal is then precipitated. Then the material can be reduced to metal by (i), washing and drying, or (ii) washing and -11-. This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) (Please read the notes on the back first (Fill in this page again)

A7 411329 __._ B7__ 5. Description of the invention (9) Dry and reduce to metal. The material can then be sintered by the present invention and then impregnated with an accelerator such as potassium, sodium, cadmium or barium acetate. Example 1 Catalyst A was manufactured according to the present invention and has a theoretical composition (ie, no loss during manufacturing) of 1.8 wt% palladium, 0.8 wt% gold, and 7 wt% potassium acetate. 1. Immersion of supporter 15 grams of KA160 Shixue pusher (4-6mm, SudChemie) was added to 1.0264 grams of sodium tetrachloropalladate trihydrate (Johnson Matthey) and 9.1 grams of deionized water in 9.1 grams A solution of 0.2655 grams of gas auric acid trihydrate (Aldrich). The addition was completed in whole and the mixture was vortexed until all the solutions had been absorbed. The impregnated support was then left at room temperature for 2 hours. 2. Precipitate the palladium and gold compounds on the support. 1.7 g of sodium silicate pentahydrate (Fisons) solution in 18 g of water was added to the impregnated support obtained in step 1. The mixture was vortexed briefly for 15 minutes to avoid the formation of "dots", and then left undisturbed overnight. 3. Reduce palladium and gold to a substantially metallic state. The water-soluble phase on the material obtained in step 2 was treated with 5 grams of 55% hydrazine hydrate (Aldrich). Washing of the L-supporting compound The water-soluble phase was slowly decanted and the material obtained in step 3 was washed 4 times with about 50 ml of water, and decanted slowly after each washing. -12- This paper size is applicable to Chinese National Standard (CNS) A4 specification (210X297mm) -------- Refer to —— t C Please read the precautions on the back before filling this page) Order

W Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Invention Description (10) — 'The formed material is transferred to a glass tube with a switch, and then every 12 hours Wash with about 1 liter of deionized water until the silver nitrate test proves negative. The material is dried overnight in strong air at 60 ° C and cooled. 5. Sintering of palladium (and gold) The supported palladium material obtained in step 4 is transferred to a horizontally placed furnace and filled into the center of a quartz line with quartz wool and the KA160 support (completely dried beforehand) fills the gap. The quartz line is placed in a steel pipe and connected to a gas supplier. The furnace temperature was raised to 15 ° C. at a fractional rate and maintained at this temperature for 2 hours under a fixed nitrogen flow. A hydrogen flow of 60 GHSV / hour was applied and the nitrogen flow was stopped. The furnace temperature was increased to 800 ° C at a rate of 30 ° C / min and maintained at this temperature for 11 hours. After this period of time, the formed material was cooled to room temperature under a stream of hydrogen. The nitrogen flow was performed again and the chlorine flow was stopped before the material was discharged. 6. Impregnation of Metal Acetate The dried material of Step 5 was impregnated with 1 g of anhydrous potassium acetate (Aldrich) dissolved in 8.8 g of water. The mixture is gently vortexed until the liquid is absorbed. The resulting material was dried again at 60 ° C overnight. Example 2 (for comparison) Catalyst B was manufactured according to the procedure of Example 1, but sintering step 5 was omitted. Example 3 (for comparison) Catalyst C was manufactured in accordance with the procedure of Example 1, but sintering step 5 was omitted and the metal load was reduced to produce a catalyst phase similar to that of Example 1. -13- This paper applies Chinese National Standards (CNS) Α4 Specification (210X297mm) ^-(Please read the notes on the back before filling this page) Ordered by the Central Consumers Bureau of the Ministry of Economic Affairs and printed by the Consumer Cooperatives 41132S A7 B7 V. Description of Invention (II) Same initial activity. Catalyst Test in Microreactor The catalyst prepared above was tested in a microreactor using the following general procedure. The catalyst was implemented at 7.8 bar and 150 ° C using a catalyst ingot (made as above, the content is as specified in Table 1) diluted with 60 ml of 1 ml glass beads and loaded in a stainless steel tube with an inner diameter of 10-11 mm. Of it. The catalyst was heated in a nitrogen stream at 7.8 bar and 160 ° C for 3 hours, and then heated at 150 ° C in an ethylene stream. The acetic acid vapor was then mixed with ethylene and passed through the catalyst over a period of at least 50 minutes. A mixture of 21% oxygen in helium was gradually added to the feed gas while maintaining a maximum catalyst bed temperature of 150 eC. The catalyst hot spot was kept at 150 ° C. The final composition of the resulting mixture was ethylene: acetic acid: oxygen: helium = 53.1: 10.4: 7.7: 28.6 (by volume) and the total gas space rate per hour was 3850 / hour. The products were analyzed in the vapor phase by hourly gas chromatography at hourly intervals. Catalyst activity Calculated in grams of vinyl acetate per liter of catalyst per hour (space-time yield, STY) and catalyst selectivity is calculated as the percentage of converted ethylene present in the product. Β data is based on complete oxygen The average values of activity and selectivity measured at 17 and 22 hours after the content was reached are reported. The results of comparing the activities of catalysts A, B, and C are shown in Table 1. -14- This paper size applies Chinese National Standard (CNS) A4 specification (210X297mm) ------------, (Please read the notes on the back before filling this page) Γ Central Ministry of Economy Printed by the Standards Bureau Consumer Cooperatives 411329 at ___ B7 V. Description of the Invention (12) Table 1. Catalyst loaded in the catalyst microreactor (g) Activity (grams of vinyl acetate per liter of catalyst per hour) Selection (%) Example 4 A 2.5 715 92.4 Example 5 B 2.0 1381 90.7 (comparative) Example 6 C 2.5 718 93.4 (comparative) The comparison of the activities of catalysts A and B in Table 1 shows that the sintering step (step 5) caused the activity of catalyst A cut back. This is consistent with the increase in particle size and the reduction in metal surface area. * Catalyst C is manufactured with a lower metal loading than Catalysts A and B; the metal loading is selected to produce the same initial activity as Catalyst A. Catalysts a and C are therefore expected to have similar initial operating behavior. However, it is expected that if the growth of particles and the surface loss of palladium metal are the reasons for reducing the initial activity, catalyst A will maintain its productivity for a longer period than catalyst C. This series is illustrated in Examples 7 and 8.催化剂 Catalyst test in large reactor -15- This paper size is applicable to Chinese National Standard (CNS) A4 specification (2! 0X297mm) (Please read the precautions on the back before filling in this 筲)

41132S A7 _._ B7____ V. Description of the invention (13) Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page). Catalysts A and C are described below for larger tubes. Tested in the reactor. 77.5 grams of Catalyst A (Example 7) and 77.5 grams of Catalyst C (Example 8 for comparison) were each loaded into a 6-foot reactor tube. The two tubes were placed in the same fluidized bed sand bath. The temperature of the bath is controlled and each tube has its own gas / liquid feed and product handling system. The nitrogen flow was started at 1 06 06 ml / min (@STP) and the ethylene flow was started at 2590 ml / min (@STP). The salo and tubes were heated to 150 ° C and the reactor pressure was raised to 115 psig. The acetic acid stream was started at 155 g / h (containing 2% by weight of water) in an evaporator and mixed with nitrogen and ethylene. A small flow of 13 g / h of acetic acid (2% by weight of water, 0.0285% by weight of potassium acetate) was introduced into the preheating zone for evaporation in the main stream. After a few hours, oxygen was started at 153 ml / min (@STP). The product stream was analyzed by on-line gas chromatography, and then condensed to produce a crude product of vinyl acetate and water. The remaining gas was discharged and β-catalyst was sampled by on-line gas chromatography to monitor its vinyl acetate production. When the catalyst is deactivated, the fixed preparation rate is initially maintained by gradually increasing the oxygen supply to a maximum content of 425 ml / min (STP). At a complete oxygen flow, the gas supply composition at a total GSHV of 2261 / hour is ethylene: acetic acid: water: oxygen: nitrogen = 49_7: 19.6: 1_3: 8.2: 21.2 (by volume). Once the complete oxygen feed rate is achieved, the fixed fabrication of the catalyst A is further maintained by gradually increasing the sand bath temperature from 150 ° C to 160 ° C. Because the two tubes are in the same sand bath, and because they lose their activity more quickly, catalyst c is manufactured to have a lower activity than catalyst A. Figure 2 shows the fluid time * 16- This paper size uses the Chinese National Standard (CNS) M size (210x297).

41132S A7 Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economics B7 V. Description of the invention (! 4) The normalized daily production of catalysts A and C as a function. Figure 2 clearly confirms that although the initial production capacity of the two catalysts is similar, after 5 days of fluid, the productivity of the comparison catalyst (Catalyst C) is lower than that of the catalyst of the present invention (Catalyst A). A 彳 stays at a productivity of about 1, while catalyst c's productivity slowly decreases over time and ends at a productivity of 0.7. At the end of the operation, the production capacity of Catalyst A was tested by adjusting the oxygen feed content and / or sand bath temperature, which corresponds to Catalyst C. Figure 2 shows that the productivity changes upwards and downwards and that Catalyst A always has a higher productivity than Catalyst C 'and it should be noted that Catalyst A exhibits a slower rate of activity than Catalyst C, even if it is its initial activity very similar. Example 9-Further testing of the catalyst using a microreactor Another two batches of catalyst were prepared according to the procedure of Example 1, but the amount of reactant used was measured by a factor of nine. After the washing and drying steps, each catalyst batch was accurately divided into 9 equal parts and impregnated with a target weight% acetic acid clock load (see Table 2). These catalyst samples were tested according to the procedures of Examples Jade No. 3. Figure 3 shows the activity formed from these catalysts and it corresponds to the catalyst activity reported in U.S. Patent No. 5179056 (this activity is inferior to the model described in U.S. Patent No. 5179056). )compared to. Figure 3 shows that the catalyst according to the present invention requires a minimum content of about 1.5% by weight potassium for activation, while for the catalyst of US Patent No. 5179056, the maximum activity is achieved at about 2.5% by weight potassium. For catalysts according to the present invention, the efficacy of accelerators is about ^ 17- This paper size applies Chinese National Standard (CNS) A4 specification (210X297 public celebration) -------- P! ----- ^- ----- r / _-(锖 Please read the notes on the back before filling this page) A7

41132S B7 5. Description of the invention (15) 1.5 to 5% by weight of potassium is approximately fixed. For catalysts based on US Patent No. 5179056, the activity begins to decrease as the loading of the accelerator increases (please read the notes on the back before filling this page) Printed by the Central Bureau of Standards of the Ministry of Economic Affairs and Consumer Cooperatives. China National Standard (CNS) A4 specification (210X 297 mm) 411329 V. Description of invention (16) A7 B7 The target of the table 2 (wt%) printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (acetic acid) is used to remove potassium from the XRF method ( Weight) Activity (vinyl acetate g / hr / catalyst 1) Selectivity (%) Activity according to model US 5179056 Activity 0 0.12 11 1 13 1 0.5 147 74.5 142 2 0.87 385 89.1 382 3 1.17 548 91 556 3 1.2 554 90.3 570 4 1.54 710 92 687 688 5 1.86 745 92.5 735 731 5 1.9 752 91.4 738 735 6 2.1 729 92.8 749 751 7 2.6 750 91.8 757 759 8 2.8 764 92.8 757 758 9 3.2 771 93.1 757 706 9 3.3 778 91.5 757 691 10 3,6 745 93.3 757 639 11 3.8 776 92.1 757 599 14 4.8 719 93.3 757 15 5.1 759 93 757 15 5.2 743 91.8 757 -19- (Please read the back and pay attention to it (Fill in this page again)

• 1T This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm). This shows that the Russian chemical agent manufactured according to the present invention can tolerate excessive concentrations of potassium acetate accelerator. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 411328 A7 B7 V. Description of the invention (17 -20- This paper scale is applicable to the Chinese National Standard (CMS) A4 specification (210X 297 mm) (Please read the precautions on the back before reading) (Fill in this page)

Claims (1)

A8 B8 r_____________________________h ++ 丨, L Λ ν amendment .; i η / L · VI. Patent Application Range i ____________ \ 3 Patent Application Order No. 086116541 Please amend the patent scope This amendment date: September 1990 1. A manufacturing A method of vinyl acetate comprising contacting ethylene, acetic acid, and an oxygen-containing gas with a supported palladium catalyst, the catalyst being prepared by a method comprising the following steps: (a) impregnating the catalyst support with a palladium compound, (b ) Convert the palladium compound into palladium that is substantially metal, and CC) in the presence of a gas formed from a reducing gas, an inert gas, or the like, at 650 to 1 Within the temperature range of 0.00eC, the supported palladium is sintered. 2. The method according to item 1 of the scope of patent application, wherein the catalyst support is impregnated with a palladium compound in a solution selected from the group consisting of water, carboxylic acid, benzine, toluene, alcohol, nitrile, tetrahydrofuran or chlorinated solvent. . 3 _ The method of claim 2 in which the solvent is water and / or acetic acid. 4_ The method according to item 1 of the patent application range, wherein the palladium compound is an acetate, sulfate, nitrate, gaseous salt of a palladium, or a palladium salt containing a marginin. 5. The method according to item 4 of the patent application, wherein the palladium compound is an acetate. 6. The method according to item 1 of the patent application range, wherein step (b) is performed by combining the le compound with a member selected from the group consisting of water-soluble hydrazine, methyl chain, sodium formate, alcohol, carbon monoxide, hydrogen, or hexene. This is accomplished by contacting a liquid or rhenium reducing agent. 7. The method as claimed in item 1 of the patent scope, wherein the catalyst contains at least weight% of princess based on the total weight of the catalyst. -21- The national standard (CNS) A4 specification of this paper is applicable (210 X 297 Gongchu) (Please read the unintentional matter on the back before filling out this page)-nt—! Staff of the Intellectual Property Bureau, Ministry of Economic Affairs, Consumer Cooperatives Seal-II ^ oi ^ II yi ^ n! Nn τι ϋ n «I ^ nn ~-I nnnn. 1 A8 B8 r_____________________________h ++, L Λ ν amendment .; i η / L \ 3 Patent Application Order No. 086116541 requires amendments to the scope of the patent. This amendment date: September 1990. 1. A method for manufacturing vinyl acetate, which comprises contacting ethylene, acetic acid, and an oxygen-containing gas with a supported palladium catalyst. The catalyst is prepared by a method comprising: (a) impregnating the catalyst support with a palladium compound, (b) converting the palladium compound into palladium that is substantially metal, and CC) reducing from a substantially The supported palladium is sintered in the presence of a gas, an inert gas, or the like. The gas formed by the rJ mixture is sintered in a temperature range of 650 to 1000 eC. 2. The method according to item 1 of the scope of patent application, wherein the catalyst support is impregnated with a palladium compound in a solution selected from the group consisting of water, carboxylic acid, benzine, toluene, alcohol, nitrile, tetrahydrofuran or chlorinated solvent. . 3 _ The method of claim 2 in which the solvent is water and / or acetic acid. 4_ The method according to item 1 of the patent application range, wherein the palladium compound is an acetate, sulfate, nitrate, gaseous salt of a palladium, or a palladium salt containing a marginin. 5. The method according to item 4 of the patent application, wherein the palladium compound is an acetate. 6. The method according to item 1 of the patent application range, wherein step (b) is performed by combining the le compound with a member selected from the group consisting of water-soluble hydrazine, methyl chain, sodium formate, alcohol, carbon monoxide, hydrogen, or hexene. This is accomplished by contacting a liquid or rhenium reducing agent. 7. The method as claimed in item 1 of the patent scope, wherein the catalyst contains at least weight% of princess based on the total weight of the catalyst. -21- The national standard (CNS) A4 specification of this paper is applicable (210 X 297 Gongchu) (Please read the unintentional matter on the back before filling out this page)-nt—! Staff of the Intellectual Property Bureau, Ministry of Economic Affairs, Consumer Cooperatives Seal-II ^ oi ^ II yi ^ n! Nn τι ϋ ^ n «I ^ nn ~-I nnnn. 1